New 2A3 SET / Simple, but gentle sounding amplifier

[mark02131]

Hi,

The Hammond 302AX model. It has two 2.5v windings, one each 6.3v and 5v.
Very useful for 2A3 amps.

I used that transformer in a 45/2A3 project, It's a very nice transformer but I did find audio signal on the HT (B+) I'm not sure but I think it's flowing through the 2.5v winding and into the HT. I am now going to use separate 2.5v transformers for the heaters of DHT tubes.

You might check for signal riding on the top of the HT.

 

[levelfive]

It's a very nice transformer but I did find audio signal on the HT (B+) I'm not sure but I think it's flowing through the 2.5v winding and into the HT.

Hi, Mark

Thanks for the information, I will check this out.
Regards, Konstantin.

 

[Akita]

Hi all,

I'm building this amp now but plan to wind all trans myself.

Because of that, It is hard to have 300-0-300v. So I plan to build a hybrid power supply but before that I need some input from you guy.

 

[levelfive]

Hi all,
So I plan to build a hybrid power supply but before that I need some input from you guy.

Hi, Akita. Do you mean topology that semiconductors used?
Like Hybrid Graetz Bridge?

 

[Akita]

Yes, Exactly.

By refer to A. Ciuffoli schematic it look like no resistor before the 100uf (1st cap)
I do the hybrid before but with a small resistor before the 100uf 1st cap.
Now I plan to put a 47uf cap. Do I still need to place a resistor before it?

 

[keantoken]

What do the symbols mean in R4-7? Roman numerals for watts?

- keantoken

 

[levelfive]

What do the symbols mean in R4-7? Roman numerals for watts?

Hi,
Yes. This is "old school" notation from soviet radio-hobbyist tradition.
Power rating table in attachment.

 

[levelfive]

If you like building it

Hi, Folks!

I have added today PayPal button.

If you like building it, if you want to support further upgrades and sound improvements or if you want to say simple "Thank You!", please make a small donation through PayPal.

I'll see how it works. Thanks.